Glossary of Weight Loss Terms

When you start your weight loss journey, it can feel like you need to learn a second language. However, the better your understanding of weight loss terminology, the more successful you might be.

From appetite suppressants to Xenical and BMI to RDA, we’ll talk you through the common terms and abbreviations so that you can focus on losing weight and making healthier choices.


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Abdominal Fat
Abdominal Fat is fat that accumulates around your middle. This central fat between your ribs and pelvis can be present under the skin and surrounding your internal organs. Abdominal fat is sometimes assessed by measuring your waist circumference.
Acxion is a popular, Mexican brand of phentermine weight loss pills. It contains phentermine hydrochloride as its active ingredient and is available in two doses: 15mg and 30mg. 
Added Sugars
Added Sugars are sugars that are added to food and drink items as part of their production. These sugars include table sugar, honey, and sweeteners. Added sugars are different from natural sugars, such as the fructose and lactose found naturally in fruit and milk.
Adipex is the most popular brand of phentermine weight loss pills in the United States. It is a prescription-only stimulant that supports weight loss by suppressing appetite, boosting energy, and accelerating fat burn
Aerobic Exercise
Aerobic Exercise is controlled by the oxygen you inhale during exercise. This type of exercise increases the breathing rate and heart rate, leading to improved lung function. In addition, this intense exercise requires fuel which the body obtains by burning fat stores. Aerobic processes can be achieved with a brisk walk, run, or cycle.
Alli is the brand name for the over-the-counter weight loss medication orlistat. Alli works by reducing the amount of fat absorbed from the intestines. When taking Alli, patients should follow a low-fat diet for best results. This will also help to avoid digestive side effects.
Anaerobic Exercise
Anaerobic Exercise occurs without oxygen and relies on the body breaking down glucose for energy. The exercise is so intense that the body does not have time to supply the muscles with oxygen. It can occur when weightlifting, sprinting, or completing a HIIT (high-intensity interval training) session.
Appetite Suppressants
Appetite Suppressants are medications or herbal supplements that reduce the appetite. This makes it easier to consume a lower-calorie diet, which can lead to weight loss. Appetite suppressants are sometimes known as anorectic or anorexiant medications.
Biliary Pancreatic Diversion
Biliary Pancreatic Diversion with Duodenal Switch involves removing part of the stomach. The small intestine is then divided into two so that one part digests food and the other transports bile.
Binge Eating
Binge Eating is a condition in which one feels compelled to overeat regularly. People who overeat may feel that they have no control over how much they eat. As a result, binge eating can lead to weight gain.
Bioelectric Impedance Analysis
Bioelectric Impedance Analysis (BIA) is an investigation that helps to assess health. An invisible current is passed through the body to determine a person’s body fat composition. When dieting, BIA can monitor improvements in body fat percentage, rather than relying on measurements of weight alone.
Body Composition
Body Composition refers to the different tissues found within the body. Essential and non-essential fat, bone, muscle, and other tissues such as organs all form part of your body composition. Your individual composition will affect your body shape and weight.
Body Mass Index
Body Mass Index (BMI) is a screening tool that relies on a calculation to determine if your weight is proportional to your height. If your BMI falls in the overweight or obese category, you may be at increased risk of weight-related health complications such as type 2 diabetes or heart disease.
Bontril is the brand name for the drug phendimetrazine tartrate. It is a central nervous system stimulant that shares some similarities with amphetamine. Bontril increases metabolism by stimulating the alpha-adrenergic system. This may aid in weight loss.
Calorie is also known as a kilocalorie. This unit is commonly used to measure the amount of energy contained within a food or drink item. The typical woman should eat around 2,000 calories per day, whereas men require around 2,500 calories daily. Those trying to lose weight will most likely need to eat fewer calories than this recommended daily allowance.
Calorie Deficit
Calorie Deficit occurs when someone consumes fewer calories than they burn through daily activities and exercise. With fewer calories available from the diet, the body must source energy from elsewhere. This can lead to fat stores being burned, so having a calorie deficit can aid in weight loss.
Carbohydrates, or carbs, are one of the key macronutrients in the human diet. Sugar, starch, and fiber are all types of carbohydrates found in fruit, vegetables, rice, and whole-grain products. Carbs are broken down to sugar to provide energy. If excess sugar is available, the body may store it as fat, leading to weight gain.
Cholesterol is a lipid (a fatty substance) that is essential for healthy cells. It is mostly produced by the liver but is also found in eggs, meat, shellfish, and dairy products. Eating too much fat can lead to unhealthy cholesterol levels, which increases the risk of heart and blood vessel disease.
Chromium is a supplement that may increase lean body mass and reduce the percentage of body fat. It is thought to achieve this by altering glucose and lipid metabolism and influencing insulin levels.
Contrave is the brand name for a combination drug containing the substances naltrexone and bupropion. This combination has an appetite suppressant effect and may help you to feel fuller sooner. This may make it easier to eat smaller portions and therefore lose weight.
Diabetes is a chronic disease in which the body does not produce enough insulin or does not respond appropriately to any insulin that is produced. Untreated, it is characterized by high blood sugar levels, which can damage organs, including the kidneys and eyes.
Didrex is the brand name for benzphetamine, a medication that modifies chemical levels within the brain. This drug suppresses the appetite and may increase the amount of fat the body burns as an energy source, aiding weight loss.
Diet is a term that may refer to the foods that a person commonly consumes or avoids each day, such as a “vegetarian diet”. It may also signify a special form of food restriction or adherence to a certain pattern of food intake with the aim of losing weight.
Dietary Sodium
Dietary Sodium refers to the salt we eat in our diet. Eating more salt than recommended can increase the risk of high blood pressure, heart disease, and stroke. Being aware of salt (or sodium) in your diet can therefore be beneficial to your health.
Dietician or Dietitian is a healthcare professional specializing in advising individuals on dietary or nutritional choices that will promote improved overall well-being. In addition, they can offer dietary advice to treat disease and prevent future diet- or weight-related complications.
Diuretic refers to a substance that encourages the removal of excess water and salts from the body. Often referred to as ‘water pills’, diuretic drugs are used to treat excess fluid by increasing urine production in the kidneys. Diuretics reduce the strain on the heart and are commonly used to treat high blood pressure and heart failure.
Energy Expenditure
Energy Expenditure is a measure of the amount of energy the body uses for biological functions such as breathing and new cell growth. It also includes any additional expenditure required for exertion, such as exercise.
Fat is required for healthy cell functioning and to absorb certain vitamins. However, it should only be consumed in small amounts. Excess fat that cannot be expended is stored in the body and can cause weight gain.
Fat Absorption Inhibitors
Fat Absorption Inhibitors prevent fat from being absorbed in the digestive tract. When an inhibitor is taken, a proportion of dietary fat passes through the gastrointestinal system and is excreted in the feces. Therefore, taking a fat absorption inhibitor such as orlistat (marketed as Alli and Xenical) can aid weight loss.
Fiber, or roughage, comes from plants. It is a complex carbohydrate that the body cannot break down. However, it remains an essential part of a healthy diet as it aids digestion and helps to prevent constipation. Eating a high fiber diet may also reduce your risk of developing bowel cancer, heart disease, diabetes, and stroke.
Food Triggers
Food Triggers are foods that you might eat out of habit rather than hunger, with strong feelings similar to addiction. Eating a trigger food can make you crave more than is necessary, leading to a vicious cycle of over-eating. These foods are likely to be highly processed, with a high calorie but low nutrition profile.
Food and Drug Administration
Food and Drug Administration (FDA) is a federal agency of the Department of Health and Human Services. It promotes and protects the health of the US population by advising on health-related matters, including the safety of weight-loss drugs and supplements.
Gastric Balloon
Gastric Balloon is a non-surgical procedure performed via the esophagus (food pipe). A balloon is filled with saline (saltwater) and placed into the stomach to reduce its capacity and increase feelings of fullness. This procedure is a temporary option, and the balloon is usually removed within six months.
Gastric Band
Gastric Band is a band that is fitted around the top of the stomach, creating a smaller pouch. Only a small amount of food fits in the pouch, so food intake is severely limited.
Gastric Bypass Surgery
Gastric Bypass Surgery uses staples to create a smaller pouch out of the upper portion of the stomach. The pouch is then connected to the small intestine to bypass the lower remnant of the stomach. As a result, a smaller amount of food can be consumed before feelings of fullness are achieved, and fewer calories can be absorbed.
Gastric Sleeve
Gastric Sleeve involves removing part of the stomach to make it smaller. As a result, far less food can be consumed before you feel full, helping to aid weight loss.
Gastric Surgery
Gastric Surgery is a surgery that is performed to prompt weight loss. Specialist surgeons can offer a variety of procedures, but surgery often aims to reduce the size of the stomach, limit food intake or minimize the appetite. Weight loss surgery is also called bariatric surgery.
Glucose is the scientific name for sugar. Glucose is the simplest form of carbohydrate and is found in many of the foods we eat. Our bodies use glucose as a source of energy.
Glycemic Index
Glycemic Index is a number that is given to food to indicate the rise the item will give to blood sugar levels within two hours. A high glycemic index (or GI) food will increase blood sugar levels more significantly than a low GI food.
Healthy Weight
Healthy Weight is often based on your body mass index (BMI). In the USA, a BMI of 19 to <25 is considered to be healthy. Compared to those with a BMI of 25 or higher, people who have a healthy weight are at a lower risk of developing weight-related diseases such as type 2 diabetes.
Heart Disease
Heart Disease is an umbrella term for medical conditions relating to the heart or blood vessels. Examples of heart disease include high blood pressure, heart attacks, or heart failure. Therefore, heart disease is sometimes referred to as a cardiovascular disease.
High Protein Diet
High Protein Diet is a form of food restriction in which foods high in protein are prioritized. Lean meat, fish, and some types of cheese are rich in protein. Eating a high protein, low carbohydrate diet could lead to weight loss.
Hydrostatic Body Fat Testing
Hydrostatic Body Fat Testing is a method of accurately assessing body fat. It involves being submerged in water on a scale to compare your underwater weight with your weight on land.
Hypertension (High Blood Pressure) is a condition in which the pressure within the blood vessels is abnormally high. Hypertension puts excess strain on the heart, which is forced to pump harder to supply blood to the rest of the body. Being overweight is a risk factor for developing this condition.
Insulin is a hormone that is produced by cells within the pancreas, an organ in the abdomen. Insulin helps to regulate blood sugar levels to keep them within a normal range. Unfortunately, people with diabetes do not produce enough insulin, which leads to high blood sugar levels and can damage blood vessels, nerves, and organs.
Ionamin is a prescription-only weight loss medication that contains phentermine resin as its active ingredient.
Keto Diet
Keto Diet is a diet that requires a high protein and fat intake, with very low carbohydrate consumption. By removing carbohydrates (and therefore sugars), the body starts to burn fat as an energy source in a process called ketosis. The keto diet can aid weight loss, but it can be difficult to maintain long term.
Ketone is the term for the chemicals that are created when the liver breaks down fats. Ketones are used as a source of energy when sugar is not available as fuel. Ketones may be produced during periods of fasting or when following a keto diet.
Ketosis is a process that occurs when the body doesn’t have enough sugar to use as an energy source. The liver burns fat to produce ketone bodies which are then used for energy. The process of fat burning can lead to weight loss.
Lomaira 8mg is the smallest dose of phentermine available on the market. It is a low-dose, butterfly-shaped tablet that patients can take up to three times per day.
Metabolism refers to the changes that occur within the body to keep us alive. In relation to weight loss, metabolism is commonly used to describe the rate at which the body uses the energy obtained from the food we eat. The energy can be used up more quickly if the metabolism is high, preventing fat deposition and weight gain.
Monounsaturated Fats
Monounsaturated Fats are a healthier form of fat. Unlike saturated fats, they do not raise the levels of unhealthy fats in the bloodstream and may even lower cholesterol levels. Monounsaturated fats are a type of unsaturated fat and are found in olive oil, avocado, and some nuts.
Muscle Mass
Muscle Mass is the proportion of your body made up of muscle, including muscle found in your organs. Muscle should make up a significant proportion of your body weight, although the exact amount depends on your age and sex.
Nutrient refers to food substances that are essential for keeping us healthy. A nutrient may be formed of protein, healthy fat, vitamins, or minerals that can be used for energy, growth, or cell repair.
Nutrient-Dense foods contain a significant amount of nutrients compared to their overall weight. Vegetables, fruit, lean meat, pulses, grains, nuts, and seeds tend to be nutrient-dense. Rather than filling up on the empty calories of sugar or processed foods, nutrient-dense foods will be of greater benefit to your health.
Obesity is defined by your body mass index (BMI). A BMI of 30 or higher signifies obesity. Obesity is associated with multiple health complications, including high blood pressure, high cholesterol, osteoarthritis, type 2 diabetes, and some types of cancer.
Orlistat is a weight loss medication that is marketed as Alli and Xenical. Orlistat prevents some dietary fat from being absorbed from the digestive tract, which can assist in weight loss. Orlistat should be taken with a low-fat diet both to prevent side effects and to maximize results.
Overweight is a diagnosis calculated using the body mass index (BMI) screening tool. A BMI from 25 to <30 is classified as overweight. As with obesity, being overweight can increase your risk of developing some health conditions.
Pancreas is an organ in the abdomen. The pancreas makes digestive enzymes that help to break down the food you eat. It also produces the hormone insulin, which regulates blood sugar levels. Being overweight can lead to type 2 diabetes, a condition in which the pancreas no longer produces enough insulin.
Phen-fen is a combination drug containing phentermine and fenfluramine. Both drugs are anorectics and were prescribed to aid weight loss. However, the FDA withdrew Phen-fen in 1997 due to its association with heart valve damage, pulmonary hypertension, and death.
Phentermine is an appetite suppressant medication that is prescribed to treat weight loss. This drug has similar properties to amphetamine and can give a feeling of extra energy. It is the most widely prescribed weight loss medication in the USA.
Phenyl Propanolamine
Phenylpropanolamine (PPA) was prescribed as an appetite suppressant to aid weight loss. It was also used as a decongestant to treat coughs and colds. However, it was withdrawn by the FDA after its use was linked with hemorrhagic stroke.
Plateau is the term used to describe a period of static weight measurements. This is positive if you have met and are maintaining your weight loss goal. However, if you are still trying to lose weight, a plateau can be frustrating. Plateau can also refer to eating the same number of calories as you expend, which is unlikely to lead to weight loss.
Polyunsaturated Fat
Polyunsaturated Fat is found in oily fish such as salmon, sunflower oil, and soybeans. It is a type of unsaturated fat and is considered a healthy part of the diet. Polyunsaturated fat includes omega-3 fatty acids essential for heart health and omega-6 fatty acids that nourish the brain.
Portion Control
Portion Control means choosing to eat a healthy amount of food. If you put too much food on your plate, you may eat it even though you are full. By only serving a small amount of food, you can reduce your calorie intake with less temptation to over-eat. This may aid in weight loss.
Protein is a macronutrient. Alongside fats and carbohydrates, it is a major dietary nutrient required for building and repairing muscles and other structures. Protein is found in meat and fish, as well as plants, grains, nuts, and seeds.
Pyruvate is produced when glucose is broken down in the body. Pyruvate is then converted into two different substances that provide energy for the cells within the body.
Qysmia is a weight loss drug that contains both phentermine and topiramate. Phentermine is an appetite suppressant, and in combination with topiramate, it works to reduce the appetite and make you feel fuller sooner. This makes it easier to reduce your calorie intake and therefore lose weight.
Recommended Daily Allowance
Recommended Daily Allowance (RDA) provides guidance on how much you should eat each day to remain healthy. Recommendations are given for daily fat, protein, carbohydrate, fiber, salt, calorie intake, and some vitamins and minerals. The Food and Drug Administration regulates it.
Refined Grains
Refined Grains are grains that started as whole grains but have had one or more of their three key parts removed. Refined grains include white flour and white rice. These grains have a lower nutritional value than whole grains, as the process of refining removes protein and other nutrients.
Roux-en-Y Gastric Bypass is another name for a gastric bypass.
Saturated Fat
Saturated Fat is sometimes known as a ‘bad fat’. Saturated fat is found in butter, coconut oil, ghee, fatty meat, cheese, cakes, and biscuits. It can increase cholesterol levels and the risk of developing heart disease. Reducing your intake of saturated fat can aid in weight loss.
Saxenda is an injectable weight loss medication. It contains the drug liraglutide, which mimics a hormone called GLP-1. Saxenda targets the areas of the brain that control appetite and food intake to assist with weight loss alongside a calorie-restricted diet.
Sentis is a popular brand of phentermine weight loss pills sold in Chile. It works to suppress appetite and boost energy to help users lose weight faster.
Serotonin is sometimes known as the ‘happy hormone’. It is a chemical that transmits messages between the nerves and stabilizes the mood. Healthy levels of serotonin may help to prevent depression and regulate sleep. In addition, high levels of serotonin may suppress the appetite, resulting in weight loss.
Serving Size
Serving Size is a standardized volume of food. It offers guidance on the correct amount of food required to meet your nutritional requirements. It differs from a portion size or portion control, which is the amount you choose to eat.
Sibutramine was marketed under the brand name Meridia. However, the FDA withdrew this appetite suppressant medication in 2010 due to concerns about associated cardiovascular disease health risks, including heart attacks and stroke.
Supplements are products taken to supplement the diet. Dietary supplements may contain vitamins, minerals, botanicals, or herbs to increase a person’s intake of essential nutrients. Supplements are available as capsules, tablets, powders, or in a liquid form.
Tenuate is the brand name for diethylpropion. This weight loss drug works by increasing certain chemicals in the brain to suppress feelings of hunger. This makes it easier to eat fewer calories and therefore lose weight.
Terfamex is a Mexican brand of phentermine weight loss pills. Available in both capsule and orally disintegrating tablet (ODT) form, this medication helps suppress appetite and boost energy.
Trans Fatty Acids
Trans Fatty Acids are a form of fat. Natural trans fatty acids are found in meat and dairy products and are not unhealthy. Artificial trans fatty acids are chemically altered to remain solid at room temperature. Examples of foods that contain artificial trans fatty acids are margarine, fried foods, and baked goods such as cakes and cookies. Artificial fats can increase cholesterol and the risk of heart disease.
Type 1 Diabetes
Type 1 Diabetes is an autoimmune disease that is often diagnosed in children and young adults. But, more unusually, it can occur later in life. As an autoimmune disease, the body attacks the cells in the pancreas that would typically produce insulin. With less insulin being produced, levels of glucose (sugar) in the blood can rise. This can lead to serious illness.
Type 2 Diabetes
Type 2 Diabetes tends to occur later in life and is associated with being overweight or obese. The pancreas produces less insulin, and the body becomes resistant to any insulin that is produced. In some cases, losing weight can improve insulin production to normalize blood sugar levels.
Unsaturated Fat
Unsaturated Fat is a healthy form of fat. It is found in vegetable oil, avocado, nuts, seeds, and fatty fish. Consuming unsaturated fat may lower cholesterol levels and reduce the risk of heart disease and stroke. Polyunsaturated and monounsaturated fats are both types of unsaturated fat.
Very Low-Calorie Diet
Very Low-Calorie Diet (VLCD) is sometimes known as a crash diet. It involves eating 800 or fewer calories per day to achieve rapid weight loss. Following a VLCD can lead to nutrient deficiency long-term, but the diet is sometimes recommended for a short period to treat morbid obesity or before weight loss surgery.
Waist Circumference
Waist Circumference is used to assess the amount of fat around your middle. An increased waist circumference may indicate that someone is overweight or obese, increasing the risk of weight-related health conditions including diabetes and hypertension. Like BMI, waist circumference is sometimes used as a screening tool for obesity.
Waist-to-Hip Ratio
Waist-to-hip ratio (WHR) is one of several measurements your doctor may use to assess whether extra fat is posing a health risk. As opposed to your body mass index (BMI), which calculates the ratio of your weight to your height, WHR compares the ratio of the waist size to your hip size. It measures how much fat is stored on your waist, hips, and buttocks.
Wegovy is the brand name for semaglutide. This once-weekly injectable medication is prescribed to aid weight loss. It mimics the hormone GLP-1 to act within the brain to reduce appetite. As a result, taking Wegovy may make it easier to resist over-eating.
Weight Cycling
Weight Cycling is sometimes known as yo-yo dieting. It refers to the cycle of losing and regaining weight in association with dieting.
Whole Grains
Whole Grains are grains that still contain all three of their main parts. Whole grains include oatmeal, brown rice, wholewheat pasta and bread, barley, and buckwheat. Unlike refined grains, the natural nutrients remain present in whole grain products, making them a healthier choice.
Xenical is the brand name for prescription-strength orlistat. Orlistat inhibits fat absorption within the digestive tract, helping to reduce fat intake even fat is consumed. For best results, Xenical should be taken in conjunction with a low-fat diet. This will also reduce the risk of digestive side effects.
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